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Drug reactions are very diverse, below are types of drug reaction related to hair and nails.
1. Diffuse non-scarring alopecia
• Exclude other causes, including iron deficiency, thyroid disease, and telogen effluvium
after a severe illness.
• Diffuse alopecia caused by drugs such as cytotoxics, anticoagulants (heparin and
warfarin), antithyroid drugs, and oral contraceptives.

2. Scarring alopecia
• Rare after chemotherapy with taxanes.

3 Increased hair growth
• Hirsutism = increased hair growth in female in an androgen-dependent pattern (normal
male sexual pattern)—face, lips, chest, arms, thighs. Causes: oral contraceptive pill, other
androgenic drugs.
• Hypertrichosis = increased hair growth at all body sites. Causes include: ciclosporin,
corticosteroids, acetazolamide, phenytoin, IFN, minoxidil, and cetuximab.

4. Nail abnormalities
Common causes: tetracyclines, antimalarials, retinoids, antiretroviral agents, and
chemotherapy agents. Drug-induced nail changes usually involve many or all of the nails
and resolve when the drug is withdrawn. Drugs may affect the nail matrix, nail bed,
periungual tissues, or blood vessels.

Nail matrix damage:
• Beau lines = transverse grooves in the nail plate caused by a temporary interruption of
cell division in the nail matrix (common). If severe, nails may be shed (onychomadesis).
(Correlates with Pohl–Pincus marks in hair shafts.)
• Nail fragility, altered rate of nail growth, leuconychia.
• Pigmentation: diffuse or in bands (longitudinal or transverse).

Nail bed damage:
• Separation of the nail plate from the nail bed = onycholysis (common).
• Photo-onycholysis (painful, may be pigmented).
• Splinter haemorrhages.
• Subungual hyperkeratosis or thickening of the nail bed.

Proximal nail fold damage:
• Periungual pyogenic granulomas (common).
• Acute paronychia, sometimes with subungual abscess (unusual).

Nail blood flow alterations:
• Ischaemic changes; subungual haemorrhages (purpura).
• Nail atrophy.

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